Accueil du site > Recherche > Séminaires > 2014 > Séminaire de Clément Deloubens le Jeudi 12 Juin 2014 de 14H à 15H

Séminaire de Clément Deloubens le Jeudi 12 Juin 2014 de 14H à 15H

Mechanical perspectives of drug delivery in the gastro-intestinal tract : Mass transfers at macro and micro scales Mechanical properties of microcapsules

par Denis Roux - 28 mai 2014

Lieu du séminaire : Salle B204 (2ème étage salle Numéro 4 - Bat B de Chimie) Campus Universitaire

Mechanical perspectives of drug delivery in the gastro-intestinal tract : Mass transfers at macro and micro scales Mechanical properties of microcapsules

Clément de Loubens

Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE)

The understanding of mixing and mass transfer of nutrients and drugs in the small intestine is of a prime importance in creating formulations that manipulate absorption and digestibility. The kinetics of release depends on the interaction between gastro-intestinal motility and the structure that contains the nutrients or the drug (i.e. food, encapsulation). The first part of this talk will focus on the recent finding concerning the fluid mechanical consequences of intestinal motility at macro and micro scales. The second part will present methods of mechanical characterisation of microcapsules.

(1) At macroscopic scale, the spatiotemporal analysis of non-propagating longitudinal contractions, i.e. pendular activity, in the small intestine of the rat was incorporated in simulations using lattice Boltzmann numerical methods. The results indicated that pendular activity could generate longitudinal dispersion of the luminal content by shear deformation in absence of propulsion.

At microscopic scale, the examination of the disposition and movement of mucosa and associated villi during contractions of the everted small intestine of the brushtail possum showed that compression of the intestinal mucosa by longitudinal contractions created short-lived microfolds, which were of similar scale to the attached villi. Simulations showed that these caused liquid digesta to be expelled from, or drawn into, intervillous spaces, significantly augmenting peripheral mixing.

(2) The mechanical behavior of microcapsules made of a cross-linked membrane in human serum albumine HSA subjected to elongational stresses are revealed. In small deformations regime, observations are coupled with AFM measurements that lead to the determination of mechanical characteristics as well as the thickness of the membrane of the container. Particularly the surfacic shear modulus Gs varies from 0.002 N/m to 5 N/m while the Young modulus varies from 20 kPa to 1 MPa. Finally we extend the study to the large deformations regime and determine the constitutive law of the membrane.

Voir en ligne : https://chimie-biologie.ujf-grenobl...


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